Title

Author

Date of Award

Degree Type

Thesis

Degree Name

Master of Science in Integrative Biology (MSIB)

Department

Biology

Major Professor

Martin Lynn Hudson

First Committee Member

Scott Nowak

Second Committee Member

Jared Taglialatela

Abstract

Proper nervous system development is required for an organism’s survival and function. Defects in neurogenesis have been linked to neurodevelopmental disorders such as schizophrenia and autism spectrum disorders. Understanding the gene regulatory networks that orchestrate neural development, specifically cascades of proneural transcription factors, can better elucidate which genes are most essential in governing early neurogenesis. Neurogenins are a family of such factors that are both sufficient and necessary for the development of neural sub-types in mice, primarily through the regulation of other factors, particularly NeuroD. The objective of this study was to evaluate previously established regulatory targets of neurogenin(ngn-1) and to identify unknown downstream targets, using the nematode Caenorhabditis elegans as a model for these studies. We find that in C. elegans, neurogenin is required for axon outgrowth, cell fate specification, and epithelial integrity during embryonic development. Using RNA sequencing and comparative transcriptome analysis we found that ngn-1 acts primarily to repress transcription, facilitating proper embryogenesis. We also identified specific candidates for activation by ngn-1, including hlh-34(NPAS1) and unc-42(Prop1), which we further validated using genetic methods. Our results identify novel pathways connecting ngn-1 to known terminal regulators, which maintain cell fate of terminally differentiated neural subtypes, and align neurogenins within the larger context of proneural transcription factors.